The use in absorbent articles of an auxiliary absorbent pad in combination with a primary absorbent pad is well known, for example, such as the so-called "diaper doubler". Such an auxiliary absorbent pad is usually placed atop the primary absorbent pad for the purpose of increasing absorbent capacity.
U.S. Pat. No. 4,501,587, to Enloe, discloses a combination of a main absorbent pad and an auxiliary absorbent pad to increase the absorbent capacity of the front section of the diaper. The main and auxiliary absorbent pads are assembled together within an enclosure.
U.S. Pat. No. 4,938,756, to Salek, describes a two-piece absorbent article. An auxiliary absorbent member is placed atop a primary absorbent member such as a diaper. The auxiliary absorbent member has a liquid transferable undersurface, on which intermittent adhesive is provided for fastening to the primary absorbent member, so that liquids are transferable between the primary and auxiliary absorbent members. The auxiliary absorbent member may be T-shaped to maximize the absorbent capacity of the auxiliary absorbent member, for example, for gender specific diaper use. While this patent construction provides a variety of pad design options, it does not address the barrier characteristics of the construction to prevent overflowing of liquids running along top surfaces of the auxiliary and primary absorbent members.
U.S. Pat. No. 3,386,442, to Sabee, discloses a diaper having liquid impermeable side strips to cover side edges of an enclosed absorbent pad. Similarly, U.S. Pat. No. 3,825,006, to Ralph, shows a diaper including liquid impermeable side flaps which overlap respective opposite side margins of an absorbent pad.
U.S. Pat. No. 4,490,148, to Beckestrom, discloses a diaper having a liquid-impermeable upstanding gathers which improve liquid containment characteristics of the diaper. U.S. Pat. No. 4,795,454, to Dragoo, discloses an absorbent garment including a liquid barrier sheet along each side margin of the article to cover and seal the side edges of the absorbent core. The liquid barrier sheet also has an upstanding portion which is intended to prevent liquid from flowing along a top surface to the edge of the garment.